The present invention pertains to thermosettable epoxy resin compositions containing an epoxy resin, boron trifluoride complexed with a primary, secondary or tertiary amine and a phosphazene compound.
Phosphazenes have been employed to cure epoxy resins as disclosed in Chem. Abstr. 81:153388e and Chem. Abstr. 82:18014k. Boron trifluoride and its complexes with ethers and amines have been known to cure epoxy resins; however, it would be desirable if the glass transition temperature of the cured products could be raised.
It has been discovered that certain phosphazene compounds can be employed in boron trifluoride amine complex cured epoxy resins to increase the glass transition temperature (Tg).